Photoaffinity labeling demonstrates binding between Ia and antigen on antigen-presenting cells
Antigen-presenting cells (APCs) bind and present antigens to immunocompetent T lymphocytes in the context of Ia molecules: however, the molecular nature of the immunogenic complexes on the surface of these cells is unknown. They have used radioiodinated photoreactive Beef insulin (BI) derivatized in the B29 position with (n-(4-(4'-azido-3'-(/sup 125/)iodophenylazo)benzoyl)-3-aminopropyl-n-oxy-succinimide) (B29-AZAP) as antigen to examine the nature of these molecular complexes. The probe was reacted with either of two B hybridoma APCs, TA3 (Ia/sup k/d/) and LB(Ia/sup d/b/) which present insulin on I-A/sup d/ and I-A/sub b/ respectively, to appropriately restricted, BI specific T helper lymphocytes (T/sub H/). Samples were photolyzed, solubilized and then analyzed by SDS-PAGE. Two protein bands of 36-kDa and 27-kDa were specifically labeled on TA3 and LB cells. Treatment of these bands with dithiothreitol or endo-N-..beta..-glycosidase F demonstrates that each is composed of a single glycoprotein. These bands are immunoprecipitable with haplotype specific but not control anti-Ia antibodies. This identifies the labeled bands as the ..cap alpha..- and ..beta..- subunits of class II MHC antigens. They conclude that a molecular complex may form between Ia and antigen on APCs and that formation of this complex does not require the presence of an antigen specific T/sub H/ cell receptor.
- Research Organization:
- Univ. of Toronto, Ontario
- OSTI ID:
- 6917290
- Report Number(s):
- CONF-8604222-; TRN: 87-005725
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:4; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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ANTIGENS
BIOCHEMICAL REACTION KINETICS
PROTEINS
LABELLING
MOLECULAR STRUCTURE
AFFINITY
ELECTROPHORESIS
HYBRIDOMAS
INSULIN
IODINE 125
LYMPHOCYTES
TRACER TECHNIQUES
ANIMAL CELLS
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LEUKOCYTES
MATERIALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HORMONES
RADIOISOTOPES
REACTION KINETICS
SOMATIC CELLS
550201* - Biochemistry- Tracer Techniques